Hi, I'm a geologist who is pondering a kitchen remodel, so I have been lurking here and enjoying all the different uses of beautiful stones. I can weigh in on this question.

"Rust," in geologic terms is just another mineral. It's iron oxide, and in mineral terms it is most likely hematite. Iron is present in many different rocks and so iron oxide is common too. Sometimes it's that traditional rusty color and sometimes its more yellow or more brown or even black. In any case it's not a flaw. If the rust colored parts follow naturally along the veining, then to me that would seem perfectly normal. What I don't like is when there is a big rusty "bloom" across big patches of the slab. Again, that is normal weathering for a rock, but I don't find it attractive.

What is the color of the veining in the non-rusty areas? Is it grey or black? It might still be hematite just with different degrees of oxidation. There is a way to tell that with a sample of the rock.

As for weaknesses, in a rock like this one there are potential weak planes along any of those colored layers. I assume the rock holds together during fabrication otherwise it wouldn't make it very far as a production-worthy stone. So I wouldn't worry about the rusty layers more than any other layers.

That said, I can't speak with much confidence on the actual piece of stone, so take this advice with a grain of salt (or perhaps a grain of quartz). But if you like it, I doubt that any visitor is going to object over the coloring.

Good luck with your quest for the perfect slab!

Karin

It would help if you have a picture to share.

I have some small areas of "rust" in my stone. The only reason they bother me at all is when I think it is a spot that needs to be wiped up and then realize it is just a little rust spot. Our stone has only been in about a month but I'm already finding I notice them less and less.
When I was first looking at granite I noticed some slabs had very large areas of rust. I was told by the sales people that some people avoid them and others like them.

Thanks for your feedback! I almost dread picking a final stone because I have so enjoyed wandering through the slab warehouses. Yesterday, I saw a slab that had random little "fish" looking designs kind of imprinted onto the slab. I commented on the fish-looking imprints to the warehouse guy and it turns out that the fish imprints are truly fossilized fish embedded in the slab! When I looked closer, I could actually see the fins, tails, shapes, everything! So incredibly cool! The 4x6 ft slab had a $12,000 price tag, so someone else will get to take that slab home!

karin - Thanks so much for sharing your knowledge. I like the term "iron oxide" better than "rust"! The gray veins range from light gray to dark charcoal. I really like the dark charcoal colors and the variations of grays, and I'm trying to see the rust/browns as a feature...

Arizonalady1 - I will try now to post pictures. Would love to have you return and share your thoughts on the slabs.

Camphappy - Thanks for sharing! I think I really like the rust, but this seems like such a permanent decision, and this decision will sit in the most open part of our new home! Two big ole' islands of it!

Here are two of the three slabs. The rust colors look a little exaggerated in the light. When looking at a whole slab in person (not so close up), the slabs come across as variations of grays.

Absolutely gorgeous! Enjoy.

Below is a somewhat current rendering of our kitchen. The White Macaubas will be on the two islands. Unless I change my mind. The perimeter countertops will be something dark and honed or leathered. The floors will be quite a bit lighter than in the rendering. Backsplash is also lighter. There is much more electrical lighting in the room now than is indicated in the picture, and the 2 walls you can't see (to the right and behind) are pretty much all windows.
Can you see the White Macaubas slabs above in this application?

Ok, so sorry to post again. I have not figured out how to post more than one jpg file in a single post...
Here is a (really) close up of one of the more significant rust areas on one of the slabs above...

One more close up, and then I'll quit for a bit! Thanks for the patience!!

Beautiful rock! Thanks for posting the pictures. The rust is certainly not a flaw in this rock. The only decision is if you like the colors or not. I understand that this is a major decision though, so good luck with your continued pondering.

Karin

That stone is gorgeous and your kitchen is going to be spectacular!!!

karin_mt and cat_mom... you are pushing me over the edge! Thanks for your feedback...

Ok if youre not taking those slabs then can I have dibs? I live in PA and It's just a short drive for me ;)
The stone seems made for your lovely kitchen to be. Go for it.

ppbenn, cat_mom, karin_mt, arizonalady1:
Well..., I hope we are all right! I bought the slabs. Thanks so much! So happy to be beyond debating this decision with myself, and your input helped move me along. Now to figure out what should go on the perimeter? I feel another thread coming along...
Thanks again!

Beautiful! I say go for it! I think the rust adds visual interest!

Nice going! Now they have to ship the slabs to TX? That's an impressive commitment. But I'm glad you've found what you like - enjoy!

I searched for this topic so I’m glad you already posted this. I’s exactly what im looking for. I think the rust allows for cool and warm colors to mix better in the design & also feel it adds visual interest as others have stated. How are you liking it after 9 years?